A short walk from the fast-food drive-throughs, taco joints and doughnut shops lining Hawaiian Gardens’ palm-tree-dotted main drag, a classroom of energetic kindergartners begins a well-rehearsed routine.

Jutting their thumbs down and contorting their faces in theatrical frowns, the kids chant, “Soda is bad!”

“Doritos?” teacher Adriana Rosas calls out.”No!” the kids yell, each making an “X” with their small arms.

Standing quietly to the side with his arms crossed, a short man in square-framed glasses smiles.

Alexander Khananashvili wrote these sing-alongs, which are heard in four elementary schools serving this blue-collar, predominantly Latino suburb east of Long Beach.

The tiniest city in Los Angeles County, Hawaiian Gardens would be easy to miss, but for the large electronic billboard on the 605 Freeway luring passersby to its casino. The town takes up less than a square mile. Nearly a quarter of its population lives below the poverty level.

But to Khananashvili, the city’s size offers an unusual opportunity. He sees a condensed and manageable space to test emerging theories that suggest keeping off extra pounds requires upending everyday food culture — at schools, in grocery stores and homes, at restaurants.

“The problem with obesity can be solved,” says Khananashvili, a self-styled community educator. “It’ll take years, but it can be solved.”

It’s been an unlikely journey for a physician who left Russia for an immigrant’s life in America 15 years ago and found success teaching the children of other immigrants how to improve their lives — even if that’s not always easy.